1. Field of the Invention
This invention relates to a light emitting diode (LED) lamp device applicable to a light source of a light emitting body. Particularly, the invention is preferably used as a light source of a planar light emitting body such as a base structure (e.g. dial) of a vehicle meter and a display panel.
2. Description of the Related Art
Generally, a lamp bulb is used to illuminate a vehicle meter and the like. Japanese Laid Open Patent Publication No. 10-197671 shows a meter illumination that uses a multi-color LED (RGB-LED).
In that invention, a light guide is disposed on a meter and an RGB-LED is disposed on an end surface of the light guide. The LED emits light into the light guide and the light is sent out through a flat surface of the light guide so as to irradiate the entirety of the vehicle meter. The LED is mounted on a flexible printed circuit board (PCB) that is dedicated to the LED. A control circuit is packaged on the flexible PCB and controls the LED to illuminate the meter with a desired color of light.
The LED lamp used in that invention is a dome-shaped type and has a major light-emitting surface along a lens surface. Specifically, the major light emitting surface is formed on a semi-spherical part about a vertex of the LED lamp. Therefore, though the light goes into the end surface of the light guide from the LED, the light is not efficiently introduced into the light guide.
On the other hand, the dedicated LED can be disposed in a special application such as the technique disclosed in the above publication. However, the LED mounted on the dedicated flexible PCB cannot be used for a general purpose. Moreover, it is difficult to substitute the LED for the conventional bulb lamp, since the bulb and the LED have different standardized sizes.
An object of the present invention is to provide an LED lamp device that is able to send light into a planar light guide at high efficiency when it is used as a light source for a planar light emitting body using the light guide.
Another object of the present invention is to provide an LED lamp device that can be used as a light source of a light emitting body in place of a bulb lamp regardless of the size difference between the bulb and the LED. This object aims at a general purpose application of the LED lamp device.
According to the first object of the invention, it relates to an LED lamp device that has a chip LED mounted on one or more surface of a substrate. It also includes a casing made of a transparent synthetic resin, the casing accommodating the chip LED and the substrate therein.
According to the first object of the invention, there is another LED lamp device that has a light guide of essentially planar shape. A chip LED is disposed on a plane perpendicular to the plane of the light guide, the chip LED emitting light directly onto an end surface of the light guide. A substrate has one or more surfaces on which the chip LED is mounted. A casing is made of a transparent synthetic resin, the casing accommodating the chip LED and the substrate therein. According to the second object of the invention, there is an LED lamp device that has an LED lamp. A power converting circuit converts an input power source voltage and an input power source current into a voltage and a current for driving the LED lamp. A synthetic resin housing accommodates therein the LED lamp and the power converting circuit. The housing fixes the LED lamp at one end thereof The housing has a locking structure on an outer peripheral surface. The locking structure is mountable on an attachment hole of a base structure.
Further objects and advantages of the invention will be apparent from the following description and the reference to the accompanying drawings, wherein preferred embodiments of the invention are clearly shown.